Double-wall structural material



Nov. 27, 1945. R. H. FoLsoM DOUBLE-WALL STRUCTURAL MATERIAL Filed Aug. 25, 1944 2 Sheets-Sheet l INVENTOR.

Nov. 27, 1945. R. H. FOLSOM DOUBLE-WALL STRUCTURAL MATERIAL Filed Aug. 25, 1944 2. Sheets-Sheet 2 Patented Nov. 27, 1945 UN I TED STAT 151$v PATENT 0F HCE.

DOUBLE-WALL srnvorumnm'mamn Robert Ht Folsom, Los- Angelesp cam; Application August. 25, 1s44',gseriarm..ssr,zra

(er o-a5 "5" Claims;

My invention concerns.- light. weight, rigid, hollow or double-wall material adapted for use in place of lumber, plywood,v wall board and. the like: in the structural arts and has for an object, to provide such a. material for. use in structures andarticles wherev light. weight. double-wall construction is. required or favorable, such as; airplanes vehicle bodies, boats, cabinets, etc., etc;, as well as the walls, partitions, floors. and roofs. respec-' tively of building-s.v

Inasmuch asthe building art presents the. greater problem in terms oflargeareas. andheav-yloads, a particular object ofthis invention is. toprovide large size units or. panels composed of. organic. or wood product materials. and embodying respectively an exterior weatherproof wall and surface so finished as to require no. further coating or finishing; a decorative; interior wall and surface so finished. as. to require no further. treatment. and which interior wall is spaced from the exterior wall a. distance. sufiicient to provide for concealing studs, joists, rafters, plumbing and the like between the two walls; .a systemot closely spaced webs interconnectingv the walls ta provide rigidity at. light weight; and..1oad bearin members. such. as studs, joists or rafters; concealed between the. walls and .socooperating. with. said webs and walls that. the. entire unit. or: panel; is stronger than would be expected forrthe limited; amount of material involved; all whereby the erectionv and interconnection of arela-tively small; number of such. units or panels may provide a building complete as interior and exterior walls. and finishes including floors. and roof.

The invention contemplates the provision ofan intermediat double-wall member composed preferably of a material selected for waterproofness, strength and durability rather than for appearances, and a pair of surfacing sheets adhered; one to each side of the intermediate member to add to its rigidity and tensile strength whileproviding. the required composition and finish at. each of the two respective sides; In keeping-with: objects of the. inventioneinconnection with buildings in particular one. of the surfacing; sheets becomes the interior wall surface. for a. corresponding part of. the building. and the otherssurfacing sheet provides the corresponding exterior surface. These units or panels may be used at. the floor of a. building in which case one. sheet. provides. the flooring surface whilethe'. other sheet is the ceiling, surface of an underneath room or space. Again the panels may be used in forming. the side. walls of. a building in. whichucase one sheetshall be weatherproof and of suitablerconn wide range of compositionstandsarchitecturaLand.

decorative schemes It is. also an object of. the nvention. to provide that. floor joists... roof; rafters wall studs, and the. like, are incorporated in the panelsbetore. they are erected. so; than-they stifien the. panel. during handling while. the. act.- of erecting. and. securing, a. single, panel wilL account-for. the. completenconstruction and. finishing of. .a..relatively .largearea of. double-wall construction in. which. not nailstflr. liketastening means are-required. except. where studs. ,ioists. rafterstand. the are ,icinedr to primary frame. such. as; plates}, ridgevpoles-wor theclike-r Inverselp it object to provide. that\a 1ig;htweight,=assembly at: the. in. termediate sheet and the twopsunfacing sheets forms av fixture whereby .totholdi severaL studs joists, rafters. or .thelikein. proper spaced parallel. relationship so. that. several may be erected and secured in. one. operatiom.

The. fabrication and: of. thin toughtsheetr materials,.suchv as the products of. the; art-0t syns thetic. plastics, in -.double.-wall construction is. another object. of the intention; itbeing known that. art. has produced. remarkably tough and. durable :sheet. materials whichare suited to the. building art insofar as. concerns; weatherproofness. and. but which, in. all but thick and expensive sheet form iaqrec tooj thin and. flexible tosuitahlyspan thezgaps; found in:usualbuildingframeslandtaredifliculttorsecure in-v place:

An; object. and advantage: of: this; invention which 1881152170 the economical. use on the thin, tough but somewhat. too flexible: products; of the art. of. synthetic plastics, thevprovision' ef-sucfr uniformly and. closely" spaced webs interconnecting. the. two: spacedi that. unsupportedareasof. sheet..materia1i are: limited itoa minor fraction Many otl'remobjects ahdtadvantages will-appear hereinafter and include economical mass production and complete weatherproofing and decoration of spaced interconnected walls at a central manufacturing point to provide a light weight rigid unit that can be shipped in panels of fifty square feet or greater with provision that the load bearing members which are to be later incorporated can be had to specification from a local mill or lumber yard.

I have illustrated my invention by panying'drawings in which Figure 1 is a longitudinal sectional view of a unit or panel before'insertion of the load bearingmembers; the section being seen on the line of Figure 2 and the scale of the drawing being approximately full size for a relatively thin building wall and about half scale for maximum thickness of walls; the large scalebeing resorted to to stress the fact that unexpectedly thin sheet material may be used.

Figure 2 is a sectional-view seen on a'line 2-2 ofFig.1.

Figure 3 is a horizontal cross sectional view seenon a line 33of Fig. 1 and showing load bearing members in place and also showing the panel shown in Fig. 1 connected to another similar' panel by weathertight interlocking means hereinafter described;

Figure 4 is a face view, on a much reduced scale, of a plurality of the said panels interconnected to form a Wall, partition, floor, roof, or the like; parts being shown as broken away near the surface to show interior details.

-Figure 5 is a fragmentary'surface view, on a scale less than that of'Figures 1, 2 and 3 but greater than that of Figure 4; of a load bearing member such as is employed to make the aforesaid weathertight joint between two adjacent units or panels.

The numerals l0, I2, l4 and I6 respectively indicate hereinafter designated parts or extents of what is known as the intermediate sheet and which is finally shaped to form what is known as the double-wall intermediate" member or part of the complete unit or panel; Any suitable sheet material is usedrangingfrom common cardboard the accomtosheet metal in some instances butpreferably the intermediate sheet is one 'of the thin, tough, waterproof and finallyrigid products of the art of synthetic plastics, such as wood veneer impregnated with syntheticresin, or laminations of paper and resin, or a compressed mixture'of wood pulp and organicbinder such as used in common wall boards. Those wood products which are first impregnated with synthetic'r'esin or the like are preferable for at one stage they can be readily bent quite acutelyas'at I |3,-'|5 and I1 respectively and-are finally rigid and waterproof while having the further advantage that surfacing sheets such as 20 and 2| may be adhered thereto by virtue of the resinbond incorporated in the saidwood product and finally become a substantially integral part of the whole.-

. For purposes of the immediately following description it will be assumed thatthe intermediate sheet is composed of one of the aforesaid combinationsof wood pulp and. resin selected for its final strength, rigidity and lack of undue brittleness., It will also be assumed that sheet 20 is adhered to the intermediate sheet by virtue of the resin bond incorporated in the intermediate sheet and that this sheet 20 is a particularly weatherresisting material such as the well known combination of phenolic resin and wood pulp or is thin sheet metal such as copper whichcan be bonded in place to a resin impregnated sheet by application of heat and pressure, or is resin-impregnated wood veneer bonded to the intermediate sheet by application of heat and pressure. Likewise it is assumed that sheet 2| is a suitably bonded plastics material selected for its durability and decorativeness and embodying in its composition a suitable coloring material; certain of the well known plastics materials being particularly decorative'as to color'and surface texture while being so waterproof as to withstand repeated cleaning with soap and water.

Said intermediate sheet may be of any suitable width and inasmuch as favorable sheet materials may be had in wide widths such as eight feet, and inasmuch as the final product is light in weight, units or panels may be made as much as eight feet in width and of greater length if required. This sheet is first extended as at I0 along what is known for the present as the indoor plane. This extent is a few inches in length only; the length of the extent being slightly greater than the final thickness of the double-wall member. Then the sheet is bent acutely at H to then extend as at l2 diagonally rearwardly and outwardly to what is known as the outdoor plane and which is in suitably spaced relationship to the indoor plane. Here the sheet is bent acutely at 13 and then extends forwardly at l4 along the outdoor plane for a few inches whereupon it is again bent acutely at l5 and extends as at l6 diagonally inwardly but rearwardly to the indoor plane which it intersects immediately adjacent bend Here the sheet is again bent acutely at I! and begins another extent Hi; the final double-wall member being several repetitions of the extents l0, l2, I4 and IS with intermediate bends |3, l5 and I! respectively. Each pair of adjacent I bends and I1 are in close abutment as are each 1 pair of bends l3 and I5 respectively on the outdoor plane. The diagonal extents or webs |2 and I6 .devide the space between the two walls into a plurality of channels l8, each of an accurately predetermined cross section.

The several edge-to-edge or juxtaposed extents II] on the indoor plane form a smooth surfaced continuous wall while the several juxtaposed extents |4 form a similarly smooth and continuous outdoor wall. In the case of some materials the abutting bends such as H and I1 and I3 and I5 become attached and weathertight but again these bends may be only in touching contact. However when sheet 20 is coextensively adhered over all extents I4 and when sheet 2| is coextensively adhered over all extents |0, any crevices which might be found between the aforesaid abutting bends will be sealed, the extents will be tied one to the other and the three-sheet product will be unexpectedly strong and rigid both longitudinally as well as transversely. As explained somewhat before, the sheets 20 and 2| may each be quite thin and flexible as they are not counted on for structural strength except that they act as seals and ties and tensile strength is particularly high in the more favorable of the thin sheet products of the art of synthetics.

For many crafts the product shown in Figures 1 and 2, without reinforcing or load bearing means, is suitable as a strong, light weight, economical substitute for lumber, plywood and the like, and can be saw out like wood. For building and certain other purposes however apertures 22 are formed in the extents |2 and 6 and ar- 7 .5. ranged in longitudinal rows from end to end of the panel so as to form longitudinal channels.

The apertures are shown as each extending from extent H)- to extent I 4 sothat each channel so formed is the full internal thickness of the double wall member, and each aperture is accurately dimensioned so that studs, joists, rafters, or the like, indicated in the drawings at 23, 23, areeach a. snug or frictional fit in the corresponding channel and no nails orthe like are required for securing the sheet material with respect to the said studs, joists, rafters, or the like. This provides that each frame member 23 supports corresponding portions of extents HI and I4 while the other margins of thechannels are formed by the corresponding accurately cut edges of extents I2 and it which abut corresponding surfaces'ofthe framemembers 23,

The aforesaid cut edges of extents I2- and I6 are soverynumerous and so closely spaced that they act to hold the frame members against distortion or deflection under loads and in this way the tensile strength of the sheet materials isput to" advantage in increasing the rigidity of load bearing frame members 23. In fact, and because of this, the invention provides that the members 23 may be thinner, more numerous and more closely spaced than in conventional building construction. As an example, these members 23 may be onl one inch or less in thickness and spaced about one foot on centers for usual wall construction. Of course in the case of floors of appreciable spans and concentrated loads it may be advisable to have the members 23 on closer centers such as six or eight inches and it maybe" required that the frame members and the wall'asa whole have a thickness of approximately six inches. However these figures are given only to show the adaptability of my invention to all types of building walls and specifications respectively. Also in connection with floors it should be explained that the indoor surfacing sheet 2| will be thicker than in other applications altho it is recognised that resin impregnated wood adhered to the intermediate sheet represents an ideal type of flooring.

The complete product preferably has the members 2-3 extending slightly beyond the other parts of the panel at each end, as shown in Figure 4, to insure loads being taken entirely by the members 23; the sheet material being in more or less of a floating and non-load-bearing position and held to the frame members by friction only.

Those skilled in various crafts or the structural arts will recognise in the finished product of m invention a remarkably useful, light weight and rigid material. The combination of the three sheets without reinforcing is unique in that actually it consists of two interconnected two-ply walls in which each outer ply is coextensive while the inner ply is made up of a pluralit of narrow, transversely elongated strips (the extents l and I4) each having each elongated edge bent angularly to give each strip the structural stiffness and advantages of a structural channel member while each bent edge of the extents on one wall or plane continues to and becomes an integral part of a corresponding bent edge of the strips or extents on the opposite plane. Further the combination has the advantage that the extents l0 and I4 form coextensive walls and the distribution of material in each wall is uniform. By having the surface sheets thin and flexible and incapable of setting up warpage strains, and by repeatedly bending the intermediate sheet as shown, any expansion or contraction within the materials is dissipated at the adjacent bend and this seems to account for the fact that theeprodk not, even without the members 23 in place,.i'svrc=smarkably fiat and true at all times and shows little or no tendency to warp under SGVEIE'GUR-L ditions,

Along each longitudinal edge I have. also shown the extents l2 and i6 cut away slightly as at 22a to provide a corresponding channel along each longitudinal edge-of the panel. two panels are to be connected edge to edgeas shown in Figures 3 and 4 particularly, a: .sf-rame member such as 23a is placed in the' space formed b adjacent channels 22a; This frame member 23a is slightly thicker than members 23 and has each of two opposed surfaces.- provided with diagonal saw slots 25 whichthere. provide; a. multiplicity of triangular blocks such as; 24i. Each block is the exact shape: of, and iszasnug; fit in the corresponding end of the. correspond! ing channel. By using a cementor adhesiveziurot; indicated) in the saw slots. before insertion of the. blocks in their respective channels, a.secureweathertight joint is provided. Thus; panels or: units may be interconnected sideby-sidetoform' a wall, or floor, or roof, or partition, of any desired length and. which is weathertight thruoutz and in which. the. studs, joists, rafters: andthe: like are fully concealed. and protected.

In some instances it may not be desirable; to; have the surfacing. sheets. applied. duringrmanuefacture. For an example, it may be. desired to.- have the surfacing sheets 20 composed. ofs'com mon roofing felt or it may-be desired to: merely coat extents 14. with built-up roofing-materials such as asphalt and gravel. Also. it may bead'esired to use common wall paper for sheetvzl to be purchased locally and to be applied on thejob. In such case the combination of the int'er mediate sheet and the frame members Z3'can beerected to form the otherwise complete building and the said surfacing sheets ormaterials then applied onthe job, For flooring common linoleum or ceramic tile, for example, are readily applied to the extents III.

In any event the well reinforced extents- Ill-and i l form substantial and coextensive-uninterrupted bases or foundations for any sheet material or the like to be applied and even common wall paper applied over extents l0, provides a smooth and sightly wall surface while in some types of buildings the appearance of extents l0 and I4 and the close abutment of bends II and I1 and I3 and It may be such that no surfacing sheets'are required.

While many structures and objects now made from wood andwood products do not require the material to be in thicknesses of several inches the product of my invention is peculiar in that thicknes does not govern weight but does increase rigidity; it being apparent now that the length of the sheet used in making the double wall member as shown in the drawings is approximately four times the length of the finished product. The thinner the final product the more numerous are the diagonal extents l2 and I6 and the more the product is resistant to compresion forces applied right angular to the surfaces, while the thicker the product the less numerous are the extents I2 and IE but the more suitable is the product for rigidity over long spans. Consequently the product of the invention, with or without members such as 22, can be used in making a wide variety of articles such as fences, chests, furniture, boats, rafts, wardrobes, doors,

benches, tables, counters, bins, airplanes, vehicle bodies,,etc., etc.

In the foregoing I have been specific as to constructionand arrangement of parts, applications, compositions, sizes, methods of articulating, types of surfacing sheets, etc., etc., but such is only y way of making a complete and practicable disclosure and shall not act to limit the scope of my invention which is of a broader nature as shown by the appended claims.

I claim: 1. In combination, a pair of double-wall units arranged in parallel relationship on a common plane, each unit comprising a sheet of rigid or-, ganic material having a short extent directed forwardly along a given plane, followed by an acute bend, followed by a second extent directed diagonally outwardly rearwardly to a second plane which is in spaced relationship to the first plane, followed by a second bend, followed by a third extent directed forwardly along the second plane, followed by a third acute bend, followed by a fourth extent directed inwardly rearwardly diagonally to the first plane, followed by a fourth acute bend, followed by several successive repetitions of the aforesaid extents and bends in the order named; the several first named extents being in edge to edge juxtaposed arrangement and forming a substantially continuous smooth surfaced wall on the first plane; the several third named extents being in edge to edge juxtaposed arrangement and forming a substantially continuous smooth surfaced wall on the second plane; the several second and fourth named diagonal extents dividing the space between the said two walls into a plurality of transverse channels each of predetermined polygonal cross section; the combination further including a load-bearing member disposed between the aforesaid units and embodying projecting triangular blocks some fitted snugly into corresponding channels of one unit and some fitted snugly into corresponding channels of the other unit.

2. In a structure of the class described a single sheet of originally plastic finally rigid material providing a pair of spaced parallel walls and a plurality of angularly disposed webs integral with and interconnecting said'walls; there being relatively inflexible bends-where the angularly disposed webs connect with said walls whereby said single sheet of-material provides a shape retaining double-wall unit; said webs each provided with intermediate apertures arranged in rows extending longitudinally of the said unit, and a plurality of joists one for and slidably inserted in each row of said apertures; said joists each having opposed surfaces of substantial' area in contiguity with corresponding surfaces of said two spaced walls and having substantial cross sectional area whereby the joists will collectively withstand applied loads several times greater than the unit alone will withstand; said joists each extending at each end beyond the corresponding termination of the unit and each end of each joist being adapted to load-transmitting connection with other structural members. a 3. The structure as in claim 2 and further including a thin flexible sheet of material applied coextensively over the exposed surface of one of the aforesaid pair of walls.

4. The structure as in claim 2 and further including a thin flexible sheet of decorative material applied coextensively over the outer surface of one of the aforesaid pair of walls and a thin flexible sheet of Waterproof material coextensively applied to the outer surface of the other of said pair of walls.

5. In a structure of the class described a sheet of originally plastic finally rigid organic material providing respectively a pair of spaced parallel walls and a plurality of angularly disposed webs integral with and interconnecting said walls;

there being relatively inflexible bend-s where the webs connect with said walls whereby the sheet of material provides a shape-retaining doublewall unit, and load-bearing members disposed between said walls and having coextensive contiguity with corresponding surfaces of both of the said pair of spaced parallel walls; said load-bearing members supporting said unit in non-loadbearing position in said structure.

ROBERT H. FOLSOM. 

